V-253981

Discussion

To reduce any risk of a denial-of-service (DoS) attack from a rogue or misconfigured MSDP router, the router must be configured to limit the number of source-active messages it accepts from each peer.

Check Content

Review the router configuration to determine if it is configured to limit the amount of source-active messages it accepts on a per-peer basis.

[edit protocols]
msdp {
    active-source-limit {
        maximum <1..1000000>;
        threshold <1..1000000>;
        log-warning <percent to log warning>;
    }
    local-address <lo0 address>;
    <additional configuration>
    peer <address> {
        active-source-limit {
            maximum <1..1000000>;
            threshold <1..1000000>;
            log-warning <percent to log warning>;
        }
        authentication-key "hashed PSK"; ## SECRET-DATA
    }
}
Note: Both the global, and the peer limit, are applied to every MSDP peer, and Junos applies the most restrictive limit. The maximum value sets the upper limit for source-active messages and the threshold value determines when Junos begins Random Early Detection (RED) dropping to alleviate congestion. The log-warning value is a percent where Junos begins generating syslog messages.

If the router is not configured to limit the source-active messages it accepts, this is a finding.